This invention relates to a damper disc usable as a clutch disc assembled in a clutch for an automobile, an agricultural machine, a construction machine etc., or usable as a damper for marine purpose.
In an automobile equipped with a manual transmission, for example, a countermeasure has conventionally been taken against abnormal sound emitted from a driving system at the time of acceleration or floating by reducing the torsional rigidity of the clutch disc. However, there exists an upper limit for the maximum torsion angle due to the structure of the clutch disc. Thus, a lower limit is produced in torsional rigidity. Further, too much weakening of the torsional rigidity of clutch would badly effect transient vibration from abrupt acceleration from engine knocking, and the like. Conventionally, abnormal sound at the time of acceleration and floating has not been avoided at the clutch disc due to that problem together with the above-mentioned structural limitation. Moreover, it is well known that a dynamic damper can be assembled in a propeller shaft etc. for the purpose of preventing the abnormal sound, but, in a clutch, there are disadvantages of an increase in number of components, an increase in cost and more complicated assembly.
An object of this invention is to prevent abnormal sound emitted from a drive-transmission system in an automobile, a ship etc.
In order to accomplish the above object of this invention, a sub-damper is provided, which comprises a torsion spring compressively provided along a circumferential line at an outer peripheral portion of a flange of a hub, a circular arc weight concentrically and freely rotatably supported by the flange with an end oportion pressed against an end face of a torsion spring, and a friction torque generating part provided between the flange and the weight.